The present invention relates generally to a steering wheel for an automotive vehicle, motor boat, and the like. More specifically, the invention relates to an improvement in a light weight steering wheel with a resin core.
For preventing steering wheel vibration, steering wheels with cores of synthetic resin have been proposed and developed recently. In such a steering wheel, a synthetic resin of high elastic modulus such as polybutylene, nylon resin, or the like is used for making the core. In the prior art, the core is provided with an elastic modulus of 30,000 kg/cm.sup.2 to 70,000 kg/cm.sup.2. For the steering wheel having diametrically extending spokes, the elastic modulus of the resin core is enough to resist the bending moment. However, various designs of steering wheels are proposed. For example, FIGS. 1 and 2 show examples of variations in steering wheels. As seen in FIGS. 1 and 2, a grip portion 1 is supported at the top of a steering shaft 2 by spokes 3 in cantilever fashion. In FIG. 1, the angle .theta. subtended by the two spokes 3 is about 90.degree.. In FIG. 2, the grip portion 1 is supported by a single spoke 3. In such constructions, particularly in the portion constituting the longer cantilever with respect to the connected portion P in FIG. 1 or the grip of FIG. 2, resistance to stress due to the bending moment of the resin core is insufficient. This leads to a limitation of possible resin steering wheel constructions.